A Reassessment of Mappia (Icacinaceae) Taxonomy Using Environmental Data Una Reevaluación De La Taxonomía De Mappia (Icacinaceae) Utilizando Datos Ambientales
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Research article A reassessment of Mappia (Icacinaceae) taxonomy using environmental data Una reevaluación de la taxonomía de Mappia (Icacinaceae) utilizando datos ambientales Rodrigo Duno De Stefano1 , Israel Loera2 , Diego F. Angulo3,4 Abstract: Background and Aims: Mappia (Icacinaceae) is a genus comprising four species inhabiting Mesoamerica and the Greater Antilles. In the most recent phylogenetic analysis based on morphological data, three species, representing a continental clade (Mappia longipes, M. mexicana and M. multiflora) sister to the Antillean species M. racemosa, were supported. Our aims in this study were to evaluate whether environmental data support the previous hypothesis in Mappia entities. Methods: In this study, we use ecological niche analysis (environmental niche modeling and niche divergence/conservatism tests) and multivariate analysis of variance (MANOVA) to test the previous morphological hypothesis at species and infraspecific level. Key results: Ecological differentiation between M. multiflora distributed from southeast Mexico to Costa Rica and M. racemosa occurring in Cuba, Jamaica, and Puerto Rico (Greater Antilles) was found, but not between the infraspecific taxa within the Antilles (M. racemosa var. brachycarpa, and M. racemosa var. racemosa). Conclusions: Our study brings an important signal of the ecological divergence between closely related species, but with disjunct patterns of distribution. Key words: Central America, environmental niche modeling, Greater Antilles, Neotropics. Resumen: Antecedentes y Objetivos: Mappia (Icacinaceae) es un género de cuatro especies que habitan Mesoamérica y las Antillas Mayores. El más reciente análisis filogenético del género basado en datos morfológicos apoyó la existencia de un clado continental formado porMappia longipes, M. mexicana y M. multiflora como grupo hermano de M. racemosa que se distribuye en las Antillas. El objetivo fue evaluar si datos ambientales soportan las hipó- tesis previas propuestas para las entidades de Mappia. Métodos: Se realizaron análisis de nicho ecológico (modelado de nicho ambiental y pruebas de divergencia/conservadurismo de nicho) y de va- rianza multivariado (MANOVA) para evaluar si existen otras líneas de evidencia que respalden la hipótesis morfológica previa a nivel de especie e infraespecífico. Resultados clave: Se encontró una diferenciación ecológica entre M. multiflora (sureste de México a Costa Rica) y M. racemosa (Cuba, Jamaica y Puer- to Rico (Antillas Mayores)), pero no entre los taxones infraespecíficos de las Antillas (M. racemosa var. brachycarpa y M. racemosa var. racemosa). Conclusiones: Nuestro estudio aporta una importante señal de la divergencia ecológica entre especies cercanamente emparentadas, pero con pa- trones de distribución disyunta. Palabras clave: Antillas Mayores, Centro América, modelado de nicho ecológico, Neotrópico. 1Centro de Investigación Científica de Yucatán, A.C. Received: April 23, 2020. To cite as: Duno de Stefano, R., I. Loera, and (CICY), Herbario CICY, Calle 43 No. 130, Col. Chuburná Reviewed: May 18, 2020. D. F. Angulo. 2020. A reassessment of Mappia de Hidalgo, 97200 Mérida, Yucatán, México. Accepted by Marie-Stéphanie Samain: July 16, 2020. (Icacinaceae) taxonomy using environmental data. 2Harvard University, Department of Organismic and Published Online first: August 17, 2020. Acta Botanica Mexicana 127: e1716. DOI: 10.21829/ Evolutionary Biology, 22 Divinity Avenue, 02138 Published: Acta Botanica Mexicana 127(2020). abm127.2020.1716 Cambridge, Massachusetts, USA. 3Universidad Autónoma de Yucatán, Departamento de Botánica, Carretera Mérida-Xmatkuil, km 15.5, This is an open access article under the 97000 Mérida, Yucatán, México. Creative Commons 4.0 Attribution-Non 4Author for correspondence: [email protected] commercial Licence (CC BY-NC 4.0 Internacional). e-ISSN: 2448-7589 Acta Botanica Mexicana 127: e1716 | 2020 | 10.21829/abm127.2020.1716 1 Duno de Stefano et al.: A reassessment of Mappia (Icacinaceae) Introduction On the one hand, Mappia mexicana and M. longipes The genus Mappia Jacq. (Icacinaceae) was described in are well-distinguished species based on their morpholo- 1797 by Nikolaus Joseph Jacquin and was forgotten un- gy and distribution. Mappia mexicana has small obovate til 1852, when John Miers assigned many new species to leaves with a rounded apex (vs. acute to acuminate leaves this genus (Howard, 1942). Baehni (1936) conducted a in all other species) and a completely glabrous flower (vs. taxonomic review of Mappia and segregated the Asiatic pubescent flowers in all other species) (Robinson and species of Mappia into a new genus, Neoleretia Baehni Greenman, 1895). It grows in thorny scrub and thorny forest (=Nothapodytes Blume). To date, Mappia consists of four in the border region between the states of Tamaulipas and species found in Mexico, Central America, and the Greater San Luis Potosí in northeastern Mexico. Mappia longipes Antilles (Fig. 1). The species are trees or shrubs characterized has a long floral peduncle (9 cm long)vs . ca. 3 cm long in all by leaves without stipules, domatia on the abaxial surface the other species (Lundell, 1942). It grows at 1300 m eleva- of the leaves, malphigiaceous hairs on vegetative and flo- tion in the cloud forest of Chiapas (southeastern Mexico) ral structures, axillary inflorescences, bracts and bracteoles (Lundell, 1942). absent, pentamerous flowers, petals bearded on theirinner On the other hand, Mappia racemosa Jacq. has surface and ovary surrounded by a disc. The group is par- elliptic or obovate leaves, a short peduncle (ca. 3 cm long) ticularly interesting because all the species, and especially and a completely pubescent flower. Moreover, it has a larg- Mappia mexicana B.L. Rob. & Greenm. and M. longipes er distribution area, occurring in dry forest in Cuba, Jamai- Lundell, are notably rare (small distribution range and few ca, and Puerto Rico (Duno de Stefano and Angulo, 2010). individuals), hence, a better understanding of the Mappia Mappia racemosa has two infraspecific taxa; M. racemosa circumscription might provide important insights for its var. brachycarpa Griseb., and M. racemosa var. racemosa conservation. with few morphological differences; number of secondary Figure 1: Geographic distribution of Mappia multiflora Lundell, Mappia racemosa Jacq. var. brachycarpa Griseb., and Mappia racemosa Jacq. var. racemosa. Acta Botanica Mexicana 127: e1716 | 2020 | 10.21829/abm127.2020.1716 2 Duno de Stefano et al.: A reassessment of Mappia (Icacinaceae) veins (7-13 vs. 7-9), apex of the leaves (acute vs. acumi- integration of these data, although with potential caveats, nate), fruit size (14-22 × 1-16 × 1-13 vs. 12-17 × 1-11 × 08 has contributed to important insights in the biodiversity mm) (Angulo et al., 2013). The most important morphologi- distribution around the globe, as well to understanding the cal difference is the fruit. The mesocarp can be fleshy or not role of ecological divergence on speciation. (Howard, 1942). However, this trait is highly variable within Ecological divergence is one of the most widely re- Mappia species (Angulo, 2006). Finally, Mappia multiflora ported processes that promotes diversification in natural Lundell occurs in the dry forest of Mexico to Costa Rica and populations (e.g., Jansson and Dynesius, 2002; Barnosky, has larger leaves than M. racemosa. Both Mappia racemosa 2005; Mittelbach et al., 2007) and has recently received and M. multiflora are morphologically similar, and have much attention (Hua and Wiens, 2013). been confused throughout their distribution area. Mappia Environmental niche modeling is a method that uses multiflora has longer leaves, 7 to 29.5 cm long (vs. 4.5 to 18 occurrence data in conjunction with environmental data to cm), secondary veins conspicuous on the abaxial surface of make a correlative model of the environmental conditions the leaves (vs. secondary veins inconspicuous), and leaves that meet a species’ ecological requirements and predict of the herbarium specimens dark green (vs. green-brown) the relative suitability of habitat (Warren and Seifert, 2011). (Angulo et al., 2013). These methods have now been applied to evaluate ecologi- Previous phylogenetic analyses with a molecular cal divergence (Rissler and Apodaca, 2007; Murienne et al., plastid marker (ndhF) and morphological data have been 2009) and are widely used in diverse biodiversity studies realized within Mappia and related groups (Angulo et al., (e.g. predicting species’ geographic potential (Peterson, 2013). The results suggest that within Mappia, there is 2003)); and species’ potential distributions under different morphological support for a continental clade (M. longipes, climatic conditions (Martínez-Meyer et al., 2004). M. mexicana and M. multiflora) sister to the Antillean Niche conservatism can be defined as the tenden- species M. racemosa. However, these relationships were cy for many ecological traits to remain similar over time. not resolved in the molecular analyses or in the combined Outside the niche, individuals are not expected to leave molecular-morphological analyses (Angulo et al., 2013). descendants, nor populations to persist, nor clades to en- Two fundamental reasons are responsible for these results: dure and proliferate (Wiens et al., 2010). However, a niche insufficient data and low phylogenetic signal of the marker shift is possible, and a new lineage can utilize a new diet, used (Wortley et al., 2005). host, habitat, and climatic regime. This